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transcranial ultrasound

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https://www.readbyqxmd.com/read/28229841/-neuroimaging-and-blood-biomarkers-in-functional-prognosis-after-stroke
#1
REVIEW
João Paulo Branco, Joana Santos Costa, João Sargento-Freitas, Sandra Oliveira, Bruno Mendes, Jorge Laíns, João Pinheiro
INTRODUCTION: Stroke remains one of the leading causes of morbidity and mortality around the world and it is associated with an important long-term functional disability. Some neuroimaging resources and certain peripheral blood or cerebrospinal fluid proteins can give important information about etiology, therapeutic approach, follow-up and functional prognosis in acute ischemic stroke patients. However, among the scientific community, there is currently more interest in the stroke vital prognosis over the functional prognosis...
November 2016: Acta Médica Portuguesa
https://www.readbyqxmd.com/read/28227349/automated-embolic-signal-detection-using-adaptive-gain-control-and-classification-using-anfis
#2
Praotasna Sombune, Phongphan Phienphanich, Sombat Muengtaweepongsa, Anuchit Ruamthanthong, Charturong Tantibundhit, Praotasna Sombune, Phongphan Phienphanich, Sombat Muengtaweepongsa, Anuchit Ruamthanthong, Charturong Tantibundhit, Praotasna Sombune, Charturong Tantibundhit, Phongphan Phienphanich, Sombat Muengtaweepongsa, Anuchit Ruamthanthong
This work proposes an automated system for real-time high-accuracy detection of cerebral embolic signals (ES) to couple with transcranial Doppler ultrasound (TCD) devices in diagnosing a risk of stroke. The algorithm employs Adaptive Gain Control (AGC) approach to capture suspected ESs in real-time. Then, Adaptive Wavelet Packet Transform (AWPT) and Fast Fourier Transform (FFT) are used to extract from them features most efficiently representing ES, which determined by Sequential Feature Selection technique...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28227290/pre-clinical-investigations-of-multi-path-propagation-in-transcranial-doppler-ultrasound-flow-phantom
#3
Alexander J Weir, Cheng-Xiang Wang, Stuart Parks, Alexander J Weir, Cheng-Xiang Wang, Stuart Parks, Alexander J Weir, Stuart Parks, Cheng-Xiang Wang
There are various practical situations in medical applications when pre-clinical investigations must be performed using a simulation environment or test bench prior to human studies. One example is the analysis of propagation channels in Transcanial Doppler (TCD) ultrasound (US), a signal processing challenge requiring the analysis of data from US waves scattered in three dimensions (3D). When examining the effects of scatterers in such channels, it is common to use a data acquisition test bench and a Doppler flow phantom...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226983/perspective-imaging-of-flow-in-arterial-model-obtained-with-continuous-wave-doppler-focusing-technique
#4
Ryo Nagaoka, Katsuhiro Sasaki, Seiichi Zama, Masaaki Nagone, Hiroshi Nagai, Yasuhito Takeuchi, Yoshifumi Saijo, Ryo Nagaoka, Katsuhiro Sasaki, Seiichi Zama, Masaaki Nagone, Hiroshi Nagai, Yasuhito Takeuchi, Yoshifumi Saijo, Yoshifumi Saijo, Hiroshi Nagai, Katsuhiro Sasaki, Masaaki Nagone, Seiichi Zama, Ryo Nagaoka, Yasuhito Takeuchi
Flowing emboli in the circulatory system cause fatal diseases such as stroke or pulmonary embolism. Conventional transcranial Doppler ultrasound for detection of emboli requires precise positioning by experienced examiner. In the present study, an easier emboli detection device by visualizing perspective view of blood vessel is proposed. The perspective image was obtained with continuous wave (CW) Doppler ultrasound from 2-dimensional array probe. CW Doppler signal from each element was focused by novel beam forming algorithm to obtain en face images at arbitrary depth to form perspective image...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28226851/transcranial-focused-ultrasound-for-bold-fmri-signal-modulation-in-humans
#5
Leo Ai, Jerel K Mueller, Andrea Grant, Yigitcan Eryaman, Wynn Legon, Leo Ai, Jerel K Mueller, Andrea Grant, Yigitcan Eryaman, Wynn Legon, Andrea Grant, Wynn Legon, Yigitcan Eryaman, Leo Ai, Jerel K Mueller
Transcranial focused ultrasound (tFUS) is an emerging form of non-surgical human neuromodulation that confers advantages over existing electro and electromagnetic technologies by providing a superior spatial resolution on the millimeter scale as well as the capability to target sub-cortical structures non-invasively. An examination of the pairing of tFUS and blood oxygen level dependent (BOLD) functional MRI (fMRI) in humans is presented here.
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28218603/frequency-and-clinical-course-of-cerebral-embolism-in-patients-undergoing-transcatheter-left-atrial-appendage-closure
#6
Nicolas Majunke, Franziska Eplinius, Matthias Gutberlet, Sven Moebius-Winkler, Ingo Daehnert, Matthias Grothoff, Stephan Schürer, Norman Mangner, Philipp Lurz, Sandra Erbs, Katharina Kirsch, Gerhard Schuler, Marcus Sandri
AIMS: To assess silent and clinically apparent cerebral embolic events in patients undergoing transcatheter left atrial appendage closure. METHODS AND RESULTS: In this prospective single-center study 28 patients underwent percutaneous closure of the left atrial appendage. In all patients a diffusion-weighted magnetic resonance imaging (DWI-MRI) study was performed before, the day after the procedure and during routine follow-up after 45 days. All patients underwent neurological assessment at the time of DWI-MRI...
February 21, 2017: EuroIntervention
https://www.readbyqxmd.com/read/28215461/the-use-of-ultrasound-for-postoperative-monitoring-of-cerebral-bypass-grafts-a-technical-report
#7
Ryan P Morton, Isaac Joshua Abecassis, Anne E Moore, Cory M Kelly, Michael R Levitt, Louis J Kim, Laligam N Sekhar
Duplex ultrasound and transcranial Doppler are valuable tools for post-operative monitoring of extracranial-intracranial cerebral bypass grafts. Here we describe our technique for the evaluation of both high-flow and low-flow cerebral bypass grafts over a nine year period. 186 bypass grafts were studied daily during the inpatient period between Jan 2005 and Dec 2014 after surgery for various cerebrovascular pathologies. There was a technical success rate of 97%. Duplex ultrasonographic flow measurements had excellent interobserver reliability with an intraclass correlation coefficient (ICC) of 0...
February 16, 2017: Journal of Clinical Neuroscience: Official Journal of the Neurosurgical Society of Australasia
https://www.readbyqxmd.com/read/28215270/decreased-cerebral-vasomotor-reactivity-in-patients-with-obstructive-sleep-apnea-syndrome
#8
Oguzhan Oz, Serdar Tasdemir, Hakan Akgun, Murat Erdem, Adem Balikci, Ahmet Cetiz, Mehmet Yucel, Umit Hidir Ulas, Seref Demirkaya, Yasar Kutukcu, Fuat Özgen
OBJECTIVE: In obstructive sleep apnea syndrome (OSAS), any of the activated neural, vascular, hemodynamic, metabolic, inflammatory, and thrombotic mechanisms may be related to increased cerebrovascular disease and risk of death; however, the possible pathophysiological process between obstructive sleep apnea syndrome and stroke has not been clearly explained. We hypothesize that alterations in vasomotor reactivity in patients may be responsible for their altered cerebral blood flow, and may contribute to the increased risk of ischemic stroke...
February 2017: Sleep Medicine
https://www.readbyqxmd.com/read/28204998/discrimination-between-emboli-and-artifacts-for-outpatient-transcranial-doppler-ultrasound-data
#9
Blaise Kévin Guépié, Bruno Sciolla, Fabien Millioz, Marilys Almar, Philippe Delachartre
This paper addresses the detection of emboli in transcranial Doppler ultrasound data acquired from an original portable device. The challenge is the removal of several artifacts (motion and voice) intrinsically related to long-duration (up to 1 h 40 mn per patient) outpatient signals monitoring from this device, as well as high intensities due to the stochastic nature of blood flow. This paper proposes an adapted removal procedure. This firstly consists of reducing the background noise and detecting the blood flow in the time-frequency domain using a likelihood method for contour detection...
February 15, 2017: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/28199523/detection-and-differentiation-of-cerebral-microemboli-in-patients-undergoing-major-orthopaedic-surgery-using-transcranial-doppler-ultrasound
#10
C Kietaibl, A Engel, I Horvat Menih, M Huepfl, G Erdoes, B Kubista, R Ullrich, R Windhager, K Markstaller, K U Klein
No abstract text is available yet for this article.
February 10, 2017: British Journal of Anaesthesia
https://www.readbyqxmd.com/read/28188214/transcranial-doppler-determined-change-in-posterior-cerebral-artery-blood-flow-velocity-does-not-reflect-vertebral-artery-blood-flow-during-exercise
#11
Takuro Washio, Hiroyuki Sasaki, Shigehiko Ogoh
We examined whether a change in posterior cerebral artery flow velocity (PCAv) reflected the posterior cerebral blood flow, in healthy subjects, during both static and dynamic exercise. PCAv and vertebral artery (VA) blood flow, as an index of posterior blood flow, were continuously measured during an exercise trial, using transcranial Doppler (TCD) ultrasonography and Doppler ultrasound, respectively. Static handgrip exercise significantly increased both PCAv and VA blood flow. Increasing intensity of dynamic exercise further increased VA blood flow from moderate exercise, while PCAv decreased to almost resting level...
February 10, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28175402/132%C3%A2-a-randomized-sham-controlled-trial-of-transcranial-magnetic-resonance-guided-focused-ultrasound-thalamotomy-trial-for-the-treatment-of-tremor-dominant-idiopathic-parkinson-disease
#12
Aaron E Bond, Robert Dallapiazza, Diane Huss, Amy L Warren, Scott Sperling, Ryder Gwinn, Binit B Shah, W Jeffrey Elias
No abstract text is available yet for this article.
August 1, 2016: Neurosurgery
https://www.readbyqxmd.com/read/28168069/hyperechogenicity-of-the-substantia-nigra-in-parkinson-s-disease-insights-from-two-brothers-with-markedly-different-disease-durations
#13
Julie M Hall, Matthew J Georgiades, Deborah A Hammond, Xiaoting Feng, Ahmed A Moustafa, Simon J G Lewis, Gabrielle Todd
We present clinical features and substantia nigra morphology for two brothers with Parkinson's disease (PD) aged 60 and 59 years. The brothers were diagnosed at 41 and 50 years of age, respectively. Both patients exhibited an abnormally large area of substantia nigra echogenicity bilaterally when viewed with transcranial ultrasound. The abnormality was similar in both brothers despite one having a much longer disease duration than the other. These findings further highlight that transcranial ultrasound is not associated with severity of clinical symptoms, but it might assist in the diagnosis of PD provided that it is combined with other variables known to precede PD...
2017: Case Reports in Neurological Medicine
https://www.readbyqxmd.com/read/28165334/sensitivity-of-simulated-transcranial-ultrasound-fields-to-acoustic-medium-property-maps
#14
James L B Robertson, Eleanor Martin, Ben Cox, Bradley Treeby
High intensity transcranial focused ultrasound is an FDA approved treatment for essential tremor, while low-intensity applications such as neurostimulation and opening the blood brain barrier are under active research. Simulations of transcranial ultrasound propagation are used both for focusing through the skull, and predicting intracranial fields. Maps of the skull acoustic properties are necessary for accurate simulations, and can be derived from medical images using a variety of methods. The skull maps range from segmented, homogeneous models, to fully heterogeneous models derived from medical image intensity...
February 6, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28163679/a-phase-locking-analysis-of-neuronal-firing-rhythms-with-transcranial-magneto-acoustical-stimulation-based-on-the-hodgkin-huxley-neuron-model
#15
Yi Yuan, Na Pang, Yudong Chen, Yi Wang, Xiaoli Li
Transcranial magneto-acoustical stimulation (TMAS) uses ultrasonic waves and a static magnetic field to generate electric current in nerve tissues for the purpose of modulating neuronal activities. It has the advantage of high spatial resolution and penetration depth. Neuronal firing rhythms carry and transmit nerve information in neural systems. In this study, we investigated the phase-locking characteristics of neuronal firing rhythms with TMAS based on the Hodgkin-Huxley neuron model. The simulation results indicate that the modulation frequency of ultrasound can affect the phase-locking behaviors...
2017: Frontiers in Computational Neuroscience
https://www.readbyqxmd.com/read/28127577/parkinsonian-motor-impairment-predicts-personality-domains-related-to-genetic-risk-and-treatment-outcomes-in-schizophrenia
#16
Juan L Molina, María Calvó, Eduardo Padilla, Mara Balda, Gabriela González Alemán, Néstor V Florenzano, Gonzalo Guerrero, Danielle Kamis, Beatriz Molina Rangeon, Mercedes Bourdieu, Sergio A Strejilevich, Horacio A Conesa, Javier I Escobar, Igor Zwir, C Robert Cloninger, Gabriel A de Erausquin
Identifying endophenotypes of schizophrenia is of critical importance and has profound implications on clinical practice. Here we propose an innovative approach to clarify the mechanims through which temperament and character deviance relates to risk for schizophrenia and predict long-term treatment outcomes. We recruited 61 antipsychotic naïve subjects with chronic schizophrenia, 99 unaffected relatives, and 68 healthy controls from rural communities in the Central Andes. Diagnosis was ascertained with the Schedules of Clinical Assessment in Neuropsychiatry; parkinsonian motor impairment was measured with the Unified Parkinson's Disease Rating Scale; mesencephalic parenchyma was evaluated with transcranial ultrasound; and personality traits were assessed using the Temperament and Character Inventory...
2017: NPJ Schizophrenia
https://www.readbyqxmd.com/read/28114163/doppler-ultrasonography-of-the-central-retinal-vessels-in-children-with-brain-death
#17
Becky J Riggs, Joanna S Cohen, Bhavana Shivakumar, Carmelina Trimboli-Heidler, Jason T Patregnani, Marijean M Miller, Michael C Spaeder, Nathan P Dean
OBJECTIVE: The purpose of this observational study is to explore if bedside Doppler ultrasonography of the central retinal vessels has the potential to become an ancillary study to support the timely diagnosis of brain death in children. DESIGN: Seventeen-month prospective observational cohort. SETTING: Forty-four bed pediatric medical and surgical ICU in an academic teaching hospital. PATIENTS: All children 0-18 years old who were clinically evaluated for brain death at Children's National Health Systems were enrolled and followed until discharge or death...
January 20, 2017: Pediatric Critical Care Medicine
https://www.readbyqxmd.com/read/28113579/functional-transcranial-doppler-ultrasound-for-measurement-of-hemispheric-lateralization-during-visual-memory-and-visual-search-cognitive-tasks
#18
Benjamin Hage, Mohammed Alwatban, Erin Barney, Mark Mills, Michael Dodd, Edward Truemper, Gregory Bashford
Functional transcranial Doppler ultrasound (fTCD) is a non-invasive sensing modality that measures blood flow velocities in cerebral arteries (CBFV) with high temporal resolution. CBFV change is correlated to changes in cerebral oxygen uptake, enabling fTCD to measure brain activity and lateralization with high accuracy. However, few studies have examined the relationship of CBFV change during visual search and visual memory tasks. Here a protocol to compare lateralization between these two similar cognitive tasks using fTCD is demonstrated...
August 26, 2016: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28094959/noninvasive-targeted-transcranial-neuromodulation-via-focused-ultrasound-gated-drug-release-from-nanoemulsions
#19
Raag D Airan, Randall A Meyer, Nicholas P K Ellens, Kelly R Rhodes, Keyvan Farahani, Martin G Pomper, Shilpa D Kadam, Jordan J Green
Targeted, noninvasive neuromodulation of the brain of an otherwise awake subject could revolutionize both basic and clinical neuroscience. Toward this goal, we have developed nanoparticles that allow noninvasive uncaging of a neuromodulatory drug, in this case the small molecule anesthetic propofol, upon the application of focused ultrasound. These nanoparticles are composed of biodegradable and biocompatible constituents and are activated using sonication parameters that are readily achievable by current clinical transcranial focused ultrasound systems...
January 23, 2017: Nano Letters
https://www.readbyqxmd.com/read/28092531/a-200-1380-khz-quadrifrequency-focused-ultrasound-transducer-for-neurostimulation-in-rodents-and-primates-transcranial-in-vitro-calibration-and-numerical-study-of-the-influence-of-skull-cavity
#20
Charlotte Constans, Thomas Deffieux, Pierre Pouget, Mickael Tanter, Jean-Francois Aubry
Low intensity transcranial focused ultrasound has been demonstrated to produce neuromodulation in both animals and humans. Primarily for technical reasons, frequency is one of the most poorly investigated critical wave parameters. We propose the use of a quadri-band transducer capable of operating at 200, 320, 850 and 1380 kHz for further investigation of the frequency dependence of neuromodulation efficacy while keeping the position of the transducer fixed with respect to the subject's head. This paper presents the results of the transducer calibration in water, in vitro transmission measurements through a monkey skull flap, 3D simulations based on both a μCT-scan of a rat and on CT-scans of 2 macaques...
January 11, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
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